The First moment of truth (FMOT):
When a shopper decides to purchase an item (e.g. reaches for the product sitting on a supermarket shelf)
The Second moment of truth (SMOT):
When the shopper gets the product home and starts to use it.
More recently Google identified the Zero Moment of Truth. This was explained as being the online decision-making process that takes the multi-channel shopper from the initial point of stimulus through to the first moment of truth.
The theory is that by being aware of these stages in the buying process means, we can craft message and experiences around these points to encourage and persuade shoppers to buy. However Google’s Zero Moment of Truth, or ZMOT as it is referred to, needs more than a brief explanation of how it actually works in practice across the a digital world. Google's model highlights that there is now a new critical moment of decision that happens before consumers get to the supermarket shelf. That regardless of the products sold, customers and shoppers (the two terms here are pretty-much interchangeable) decision on what product to buy is made up. However, it is not necessarily persuaded by just one factor or one message via a single source… but by a complex combination of lots of messages, many of which are via digital marketing channels.
You can find out more about it here: http://www.zeromomentoftruth.com
However these models aren't really that new or revolutionary. Back several years ago I used the acronym AIDA in several posts to refer to a very similar marketing concept. This explained that there are 4 steps along the path to purchase of: awareness, influence, decision and action. This process takes the shopper up to the point when they commit themselves to purchasing… in other words up to the first moment of truth (FMOT).
In my opinion… What Google has done with ZMOT is to give a name to the two steps of influence and decision, shaped for the modern generation of multiple channel users.
Or to break it down in a way that I find easy to understand, I've created the following diagram which shows how I think these different approached come together: